Open top containers, such as vehicle bodies, are often used to store or transport dry bulk materials. These types of containers or vehicles are easy to load and unload because the upper portion of the container is open or not covered. There are risks, however, when using open top containers or vehicle bodies if the contents are exposed, for example, to weather and transport-related conditions. As a result, many open top containers or vehicle bodies are provided with tarpaulin cover systems. Sometimes such systems use drive units in order to selectively retract (uncover) and extend (cover) a tarpaulin over the open top container.
U.S. Pat. No. 8,864,212, (“'212 patent”) all of the details of which are incorporated herein by reference thereto, discloses drive units for tarpaulin cover systems. In general, these drive units include a gear arrangement for controlling the selective covering and uncovering of the open top container. The drive unit is used with a cover system operating along the lines of U.S. Pat. No. 4,189,178, all of the details of which are incorporated herein by reference thereto. In such cover system a plurality of support rods span opposite side walls of the truck body or container. A flexible tarpaulin is mounted to the support rods. An endless cable is located at each of the side walls for rotation around pulleys at each of the front end and back end of the container. One of the rods is fastened to each of the cables so that when the cable is moved in either a clockwise or counterclockwise direction the fastened rod moves with the cable in a covering or uncovering direction. As the fastened rod moves, it pushes the tarpaulin and other rods toward one end of the container to expose the open top. Conversely, when the fastened rod is moved in the opposite direction, it pulls the tarpaulin and the other rods toward the opposite end of the container so that the tarpaulin covers the container. The drive units shown in the '212 patent generally include intermeshing gears which control the movement of the cables.